This application proposes to continue a nearly 40-year program of research that has monitored the substance use of American Indian (AI) youth living on or near reservations. It is the only study of its kind to provide ongoing surveillance data of what has historically been the most at-risk group of youth for substance use in the nation. We will continue to collect annual substance use data from 7-12th grade AI youth along with key risk and protective factors. Collection of new epidemiologic data will permit us to track recent trends in levels of use, with attention focused on recent high levels of marijuana and OxyContin and a resurgence in the use of inhalants. An additional component of this application will include the initiation of a longitudinal study of AI 6-7th grade middle school youth. This portion of the study is designed to answer (1) what is the nature of parent-child communication about drugs and alcohol, (2) what are the substance use trajectories, (3) what are the predictors and outcomes of early vs. late initiation, and (4) what explains the changing patterns of use from middle school to high school beyond the effects of school non-attendance/dropout. 2.